SOLUTION: In how many ways can 6 people be arranged so that they form a circle between them; and if 2 particular people of the 6 people quarell, how many arrangements must be made if the qua

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Question 1134223: In how many ways can 6 people be arranged so that they form a circle between them; and if 2 particular people of the 6 people quarell, how many arrangements must be made if the quarellsome pair must not stand next to each other?
Answer by ikleyn(52798) About Me  (Show Source):
You can put this solution on YOUR website!
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(a) In how many ways can 6 people be arranged so that they form a circle between them;
(b) and if 2 particular people of the 6 people quarrel, how many arrangements must be made if the quarrelsome pair
must not stand next to each other?
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            Pay attention on how I edited your post to separate and clearly show that there are TWO QUESTIONS here.


(a)  There are  n%21%2Fn = (n-1)!  circular arrangements of n objects.

     In this case n = 6, so there are (6-1)! = 5! = 120 circular arrangements of 6 persons.



(b)  Among these 120 circular arrangements, there are ONLY TWO, where the opponents are neighbors. 


    So, the answer to question (b) is  120 - 2 = 118 circular arrangements.

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On circular arrangements,  see the lesson
    - Persons sitting around a cicular table
in this site.

Also,  you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lesson is the part of this online textbook under the topic  "Combinatorics: Combinations and permutations".


Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.